Conventional sensors often sense at least one rotation characteristic of rotating elements. Rotating characteristics generally describe characteristics that at least partially describe the rotation of the rotating element. For instance, this may involve angular velocities, rotary frequencies, angular accelerations, angles of rotation, angular position or other characteristics which may characterize a continuous or discontinuous, regular or irregular rotation or revolution of the rotating element. Examples of such sensors are described in Konrad Reif (Publ.): Sensoren im Kraftfahrzeug [Automotive Sensors], 2nd edition, 2012, pages 63-74 and 120-129.
For instance, a position of a camshaft of an internal combustion engine relative to a crankshaft can be ascertained with the aid of what is generally referred to as a phase sensor employing a Hall-effect sensor. Typically, a trigger wheel is mounted on the rotating axis. Teeth may be situated on the trigger wheel which are sampled by the Hall-effect sensor when the camshaft is rotating. In German Patent Application No. DE 10 2012 213 539 A1, for instance, a method is described for ascertaining a phase position of an adjustable camshaft of an internal combustion engine which includes a trigger wheel and a camshaft adjuster. The phase position of the camshaft is ascertained on the basis of phase flank interrupts triggered by the trigger wheel, and a model that is a function of at least one operating variable of the camshaft adjuster.
However, methods of this kind do not allow continuous position sensing. Absolute angle sensing in a measuring range of 360° is not possible. Also, the resolution is limited due to the small diameters of the used trigger wheels. These small diameters result in minimal gap sizes that must be taken into account. In addition, an absolute position determination is possible only in a dynamic case, when the trigger wheel is rotating. An instantaneous availability of the absolute positional value when switching on the voltage supply, i.e. a true power-on function, is therefore not provided. Especially in a startup of an engine of the internal combustion engine, a precise position is not known. Apart from that, such methods are highly sensitive with regard to magnetic interference fields.
U.S. Pat. No. 7,499,878 B2 describes an inductive linear and rotary position sensor. A device having an excitation coil and a receiver coil is described. The excitation coil is excited by an excitation source and generates a magnetic flux. The receiver coil generates a receive signal through an inductive coupling between the excitation coil and the receiver coil.
Despite the improvements brought about by such sensor devices, there is still room for improvement. Sensor devices of this type may have a complex structure, which particularly means that a simple installation and de-installation are not possible.